五道河林场天然次生林林种结构的研究

对五道河林场天然次生林分布的土层厚度和坡度因子分析表明 ,土层厚度小于 30cm的薄土层以及坡度 >2 5°的中、厚土层次生林总面积为 2 390 .1hm2 ,占全场天然次生林总面积的 83.5 % ;而土层厚度≥ 30cm同时坡度又≤ 2 5°的次生林总面积只有 4 74 .2hm2 ,占全场天然次生林总面积的 16 .5 % ,说明该场次生林分布地段“生态脆弱性”大 ;提出五道河林场天然次生林以发展水源涵养林、用材林、经济林的林种结构 ,并用层次分析法确定 3林种的适宜发展比例为 72 .7%、18.6 %、8.7% .

Species structure of natural secondary forest in the Wudaohe farm

The analysis of soil thickness and slope gradient in natural secondary forest of the Wudaohe forest farm showed that the area of the secondary forest whose soil thickness was lower than 30 cm and slope gradient was higher than 25 degrees was 2390.1 hm2, covering 83.5% of its total area, while the area with soil thickness of higher than or equal to 30 cm and slope gradient of lower than or equal to 25 degrees was only 474.2 hm2, covering 16.5% of the total. It is suggested that the secondary forest is ecologically fragile, and this forest farm should develop a mulriple forest including waterhead-protection forest, lumber stand and economic forest. It was shown by analytic hierarchy process (AHP) that the suitable ratio of three forest types is 72.7%, 18.6%, 8.7%, respectively.